1. Technical Field
The present invention relates to a vehicle body structure of a vehicle and more particularly relates to a front structure of a vehicle body that can enhance safety in a small overlap crash.
2. Related Art
There are cases of accidents where a vehicle crashes with an oncoming vehicle or an object installed on a road. While considering a crash with an oncoming vehicle, the following matters will be described. However, the description is not limited to this kind of crash. The same matters also apply to a crash with an object installed on the road.
Crashes are commonly categorized into three cases:
(1) a full-width front crash in which a vehicle centerline of an oncoming vehicle coincides with a vehicle centerline of the vehicle body of a vehicle of interest;
(2) a frontal offset crash in which a vehicle centerline of an oncoming vehicle does not coincide with a vehicle centerline of the vehicle body of a vehicle of interest (for example, overlap of 40%); and
(3) a small overlap crash in which an oncoming vehicle crashes with a portion further toward the outside than a main frame of the vehicle body of a vehicle of interest.
In the case of a full-width front crash and a frontal offset crash out of the three types of crashes, the main frame can absorb an impact force. This is because the main frame is usually provided with an energy absorbing crush box that absorbs an impact force and because the main frame itself is designed so as to absorb the impact force.
A member for absorbing the impact force in the case of a small overlap crash is rarely provided in a vehicle. Consequently, in the case of a small overlap crash, the vehicle body absorbs the impact force and turns around an axis extending in the upward and downward directions in the vehicle body, thereby providing safety for a passenger or passengers in the vehicle.
Such a technology is disclosed in Japanese Unexamined Patent Application Publication (JP-A) No. 2012-214211.
However, in JP-A No. 2012-214211, although a reinforcing unit which interconnects an upper frame and a main frame is provided, a portion of the main frame, to which the reinforcing unit is connected, is not reinforced in comparison with the other portions of the main frame. As a result, it is necessary to reinforce the whole main frame. This causes a problem of an increase in weight.